1. Field of the Invention
The present invention generally relates to the field of semiconductors. More particularly, the invention relates to transistor semiconductor structures.
2. Background Art
MOS (Metal Oxide Semiconductor) transistors, such as Lateral Diffusion Metal Oxide Semiconductor (LDMOS) transistors, can be utilized as power transistors in high voltage switches and power amplifiers in cell phones and other wireless communication devices, as well as other types of applications that require a high power transistor. A MOS transistor, such as an LDMOS transistor, is generally utilized to provide an increased breakdown voltage. However, when utilized as a switching device, it is desirable for a MOS transistor, such as an LDMOS transistor, to have a low on-resistance (Rdson), which refers to the source-to-drain resistance of the transistor when it is turned on.
Conventionally, an increased breakdown voltage can be achieved in a MOS transistor, such as an LDMOS transistor, by increasing the drift region between channel and drain. However, increasing the drift region between channel and drain can cause the on-resistance of the MOS transistor, such as an LDMOS transistor, to increase, which is undesirable. Thus, in a conventional MOS transistor, such as a conventional LDMOS transistor, it is difficult to achieve both an increased breakdown voltage and a reduced on-resistance.